In gas Metering and Pressure Reduction Stations, the gas is pre-heated before the pressure is dropped to prevent the formation of hydrates which can cause damage to the pipeline and associated equipment. The typical pressure reduction varies between 400 to 900 PSIG (pounds per square inch gage) for main transmission gas lines to local distribution lines and from 50 to 95 PSIG from local distribution lines to consumers. When gas is depressurised the temperature drops. The rule of thumb is that for every 100 pounds of pressure drop across a valve the gas temperature will drop by 7 F. When the same pressure is dropped across a gas expander the temperature drop is three times greater (21 F per 100 pounds pressure) because work is done, typically the shaft from the gas expander is connected to a power generator or a compressor. To thermal heat required to prevent formation of hydrates is normally provided by hot water boilers, heaters or waste heat from; gas turbines, gas engines or fuel cells. The products of combustion and or emissions from the above heating sources, are released to the atmosphere. The gases emitted from a fuel cell have a very high concentration of carbon dioxide thus making it economically attractive to recover it as a consumable product. The gases emitted from combustion applications can also be recovered but the economies of scale are not as attractive as a fuel cell due to a much lower concentration of carbon dioxide in the emissions stream.